Numerous types of vehicles are frequently used on terrain on which it is difficult for pneumatic tires to operate. Both military vehicles, such as tanks and armored personal vehicles, and civilian vehicles, such as tractors and recreational vehicles, are operated on terrains, such as sand surfaces, which are very soft. Pneumatic tires are generally incapable of efficient operation on such soft surfaces as they tend to burrow into the surface rather than riding across the surface.
Tracked vehicles have been developed for use on terrains on which wheeled vehicles are impractical. See for example U.S. Pat. Nos. 3,361,488; 3,688,858; 3,734,577; and 3,955,855. On many types of terrains, these vehicles provide improved performance relative to the performance of wheeled vehicles. Still, difficulties are encountered with existing tracked vehicles.
Originally, tracked vehicles were provided with tracks made of a plurality of metallic links or shoes pivotally attached to each other to form an endless track.
With the development of elastomeric traction bands and endless tracks, numerous exterior tread patterns adapted to be used on various types of terrain have been designed. For instance, some tread patterns of certain tracks have a large ground contacting surface which is more adapted to be used on hard surfaces such as asphalt and concrete, but which provides less traction on soft surfaces such as soil and sand. Tread patterns adapted to be used on soft surfaces have also been developed, but they generally do not have a very good durability on hard surfaces.
On agricultural vehicles and other tracked farming vehicles such as tractors, one type of tread pattern is commonly used and generally corresponds to the chevron pattern. This particular tread pattern generally gives an adequate traction on most terrains, which is very important for agricultural vehicles. However, due to the configuration of the chevrons, conventional chevron tread patterns typically suffer from requiring more energy to bend the track thereby increasing rolling resistance and ultimately, fuel consumption.
There have been attempts to reduce the energy required to bend endless tracks having generally chevron tread pattern. In U.S. Pat. No. 6,241,327, the traction lugs forming the chevron pattern are provided with cuts which open during bending of the track. However, these cuts significantly reduce the structural integrity of the traction lugs and thus of the track and ultimately produce only limited results. In U.S. Pat. No. 6,510,913, the chevron tread pattern is formed by several independent traction lugs. By dividing the chevron pattern into several traction lugs, the contact surface of the traction lugs is generally reduced, thereby increasing the level of vibration.
Hence, there is a need for an improved traction band which mitigates the shortcomings of prior art traction bands.